Deductive reasoning is central to human intelligence and plays a fundamental role in the learning and understanding of fundamental concepts during childhood. Deductions also contribute significantly to mathematical and language learning. Given the central role of deductive reasoning in education, it is critical to advance our understanding of the cognitive and neural underpinnings of its development. Neuroimaging research in adults suggests that the brain regions that are engaged in deduction partially depend upon the type of task. For example, posterior parietal regions that have been linked to visuo-spatial processing have been implicated in linear relational reasoning (e.g., Tom is taller than Bill, Bill is taller than John, therefore Tom is taller than John), whereas left inferior fronal regions associated with verbal processing have been implicated in categorical reasoning (e.g., All Tulips are Flowers, All Flowers are Plants, therefore All Tulips are Plants). However, neuroimaging studies in adults also show that the left rostro-lateral prefrontal cortex is involved in both relational and categorical reasoning, suggesting a more general role for this region in the manipulation and integration of the premises of all types of reasoning problems. Although there have been several neuroimaging studies in adults and behavioral studies in children, nothing is known about the neural basis of the development of deductive reasoning in children. This project will use functional magnetic resonance imaging (fMRI) to investigate the neural development of relational and categorical reasoning in typically developing children (8-9 versus 12-13 year olds). We will examine differences in signal intensity using conventional fMRI analyses, but we will also examine differences in effective connectivity using dynamic causal modeling (DCM). The results of this project will indicate how deductive reasoning emerges and interacts with spatial and verbal systems during childhood and early adolescence. By identifying the neural development of deductive reasoning in typically developing children, our study will also provide the necessary groundwork for future studies that will investigate how this developmental trajectory differs in children with specific language impairment and dyscalculia.